SageBrush wrote: ↑
Sun Aug 18, 2019 10:28 am
Oilpan4 wrote: ↑
Sun Aug 18, 2019 9:43 am
Big difference between 100% and "near 100%".
What is the "big" difference ?
That you've got to keep the fossil fuel plants around, man and maintain them even though it gets little use, which boosts the system costs well above what the PV/Wind/Battery electricity alone costs. Working from memory so don't hold me to exact values, but as part of the Energiewende Germany added something like 60 GW of renewable generating capacity over about 10 years (IIRR 80-90% increase over their existing capacity at the time), but decreased their fossil fuel capacity essentially not at all - IIRR, they actually decreased the % of NG generation and boosted their coal generation, in particular their brown coal (lignite), the dirtiest coal there is. Actual generation only increased by around 9% over that period - all the renewables still had to be backed up by fossil fuels when the sun didn't shine and the wind didn't blow. which is the main reason why the average German household paid 29.16 Eurocents/kWh in 2018 (some of that due to excessive renewable feed-in tariffs that have since been reduced for new construction). And Germany has excellent interconnections already, something that the U.S. lacks and will have to pay for.
So, until renewables can cover 100% of the demand 100% of the time, which will require cheap mass storage, you've still got to keep the dirty plants around (and pay to keep them operable). We can certainly reduce the amount of time they're operating and reduce emissions, but as long as they're needed for backup we've still got to pay for them, and the less they're used the more each kWh they generate costs. We still want to get rid of them, but it won't be cheaper, until mass storage is.